The demand for high bandwidth telecommunication channels has resulted in the dramatic growth in optical communication transmission. Generally, these optical communication systems are built upon optical fiber transmission. Optical fibers generally can be formed from a glass material with desirable optical properties.
Optical fibers are generally very thin. The fibers generally have a core with an index-of-refraction different from a cladding layer surrounding the core. In particular, generally a core has a higher index-of-refraction than the cladding such that the light of a selected wavelength undergoes total internal reflection at the boundary between the core and cladding to keep the light within the core. The difference in index-of-refraction can be introduced by selection of the composition of the core materials to be appropriately different from the composition of the cladding material. In addition, the composition of the optical materials can be selected to alter optical properties of the fiber, such as absorption and emission properties.
Optical fibers are generally pulled from a larger block of glass material. The block from which the fiber is puller is called a fiber preform. The fiber preform is heated to an appropriate temperature to pull a fiber at a suitable rate with a desired thickness. The composition of the preform determines the resulting composition of the resulting fiber.